Time display mechanism

ABSTRACT

A time display mechanism for use with the movement of a timepiece, which movement has separate hour and minute shafts. The mechanism comprises separate hour and minute display rotors to be mounted on and rotatable with their respective shafts. The hour display rotor is marked completely around its periphery with indicia indicating hours, conveniently 0 to 12 and the minute display rotor is marked with the indicia 0 to 60 about a portion of the minute display rotor surface leaving a space between the 0 and 60 marks, which space is equivalent to the spacing between two successive hour markings on the first display rotor. An indicator is disposed over both display rotors to indicate the time. Two alternative means are provided for moving the indicator at substantially the same speed as the hour display rotor during each hour but at the end of the hour to shift the indicator rapidly across the space between the 60 and 0 marks to assume a position over the next following hour indicia. The indicator may comprise a pointer or, alternatively, a movable shutter having a window therein for indicating hours and a pointer for indicating minutes.

United States Patent 1191 Robin 1 11 3,841,086 1 51 Oct 15, 1974 TIMEDISPLAY MECHANISM [76] Inventor: Maurice Robin, 15 ter, Allee de laPepiniere, 92 Suresnes, France [22] Filed: Nov. 6, 1973 [2]] Appl. No.:413,243

[30] Foreign Application Priority Data Nov. 17, 1972 France 1. 72.40990[52] U.S. Cl. 58/125 C, 235/] C [51] Int. Cl. G04b 19/02 [58] Field ofSearch 58/125 C; 235/] C [56] References Cited I UNITED STATES PATENTS3,712,050 1/1973 Kawada 58/125 c Primary Examiner Edith Simmons JackmonAttorney, Agent, or Firm-Clelle W. Upchurch [57] ABSTRACT A time displaymechanism for use with the movement of a timepiece, which movement hasseparate hour and minute shafts. The mechanism comprises separate hourand minute display rotors to be mounted on and rotatable with theirrespective shafts. The hour display rotor is marked completely aroundits periphery with indicia indicating hours, conveniently 0 to 12 andthe minute display rotor is marked with the indicia 0 to 60 about aportion of the minute display rotor surface leaving a space between theO and 60 marks, which space is equivalent to the spacing between twosuccessive hour markings on the first display rotor. An indicator isdisposed over both display rotors to indicate the time. Two alternativemeans are provided for moving the indicator at substantially the samespeed as the hour display rotor during each hour but at the end of thehour to shift the indicator rapidly across the space between the 60 and0 marks to assume a position over the next following hour indicia. Theindicator may comprise a pointer or, alternatively, a movable shutterhaving a window therein for indicating hours and a pointer forindicating minutes.

10 Claims, 8 Drawing Figures 1 TIME DISPLAY MECHANISM The presentinvention relates to a time display mechanism for displaying hours andminutes.

It is known to replace the hour and minute hands in a timepiece such'asa clock or watch by two drums driven so as to rotate by thecorresponding axles of a clockwork movement.

These drums indicate the hours and the minutes respectively.

According to the present invention there is provided a time indicatingmechanism comprising a first display rotor having indicia thereonrepresenting hours and having means for connection to an hour shaft of atimepiece movement, a second display having indicia thereon representingzero to 60 minutes with a spacing between the 60 and minute marksequivalent to the spacing between two successive hour markings on thefirst display rotor and having means for connection to a minute shaft ofa timepiece movement, an indicator mounted over said first and seconddisplay rotors to indicate the time in hours and minutes, and indicatormoving means for moving the indicator, during each hour, in the samedirection as the first display rotor, at a speed which is a function ofthe speed of the first display rotor to maintain said indicatorsubstantially on the same hour marking and for shifting the indicatorrapidly in the opposite direction through 'a distance equivalent to thespacing between the 60 and 0 minute marks at the end of each hour, inorder to indicate the next following hour.

The present invention further relates to a timepiece having hour andminute drive shafts and a time display mechanism in accordance with thepresent invention of which the first display rotor is in drivenengagement with the hour shaft and the second display rotor is in drivenengagement with the minute shaft;

If desired, the pointer moving means may shift the pointer in accordancewith the continuous forward movement of the hour display rotor and thereading of both the hours and the minutes is taken opposite the pointer.

Preferably the minute display rotor is furthermore scaled from 00 to60through an arc of 330, a dead angle of results from this and at the60th minute the pointer moves backwards by 30 to appear opposite thenext hour and the scale 0 minute.

The display rotors may comprise drums, discs or concentrically disposedannular members.

This display mechanism serves to prevent any ambiguity in reading thetime when one hour passes to the next.

Embodiments of the present invention will now be described, by way ofexample, with reference to the accompanying drawings, in which:

FIG. 1 is a view in elevation of one embodiment of FIG. 2 is a view incross-section along the line II--II.

the time display mechanism along the line 1-1 of FIG.

FIG. 6 is a view in crosssection of the embodiment represented in FIG.5;'

FIG.. 7 is a perspective view of a further, simplified embodiment of theinvention, and

FIG. 8 is a view in cross-section of the embodiment of FIG. 7.

FIGS, 1 and 2 represent a time display mechanism for displaying hoursand minutes which comprises a support frame 1 in which are rotatablymounted a minute shaft 2 and an hourshaft which are connected in a knownmanner to for example a clockwork or electric movement not shown in thedrawing.

A display rotor in the form of a drum 4 is fixed at one of its sides tothe'minute shaft 2 and rests at its other side against a stud 5 which isfirmly fixed to the support frame 1. The drum 4 has a scale of minutesfrom 0 to 60, distributed over 330 of the peripheral surface thereofwith a dead angle a of 30 between the 00 and 60 marks (FIGS. 3 and 4).

Another display rotor in the form of a drum 6 which carries a scale ofhours from 1 to 12 is fixed on the hour shaft 3.

An indicator in the form of a pointer 7 firmly fixed to an arm 8 mountedso as to rotate freely around the shaft 2 is located opposite the hourdrum 6 and the minute drum 4, the pointer 7 simultaneously indicatingthe hours and the minutes.

The arm 8 possesses an elongate aperture or slot 9 in which is mounted astud l0 fixed to one end of a lever 11, which is mounted at its otherend about a pivot pin 12 attached to a lug 13 firmly fixed to thesupport frame 1. i

In its middle part,the lever 11 possesses a boss 14 by means of which itrests against a snail cam 15 which is firmly fixed to, and rotates with,the minute shaft 2 and which makes one revolution per hour.

The cam 15 possesses a spiral-shaped edge 16 of which the parts havingthe minimum and maximum radii are joined by a radial face 17.

The device operates in the following manner:

Both the minute drum 4 and the hour drum 6 are driven by theirrespective shafts, so as to rotate continuously in the direction of thearrow F; the arm 8 which is subject to the action of the cam 15 throughthe interengagement of the spiral-shaped edge 16 and the lever 11, movesin the direction of the arrow F as does the pointer 7, that is to say inthe same direction as the hour drum 4, in order to balance the forwardmovement of the hour drum 4 and to hold the pointer opposite theparticular hour indicated on the hour drum 6.

At the sixtieth minute, when the pointer indicates for example 9 hours60 minutes, the boss 14 of the lever 11 is situated opposite the radialface 17 of the cam 15 (FIG. 1) and passes from a large radius to a smallradius of the spiral shape edge 16. As the lever 11 falls, for exampleunder the influence of gravity or a spring bias, it causes the arm 8 andthe pointer 7 to shift or move backwards in the direction of the arrow Fin the opposite direction to that F in which the drums rotate. The shiftcorresponds to the dead angle a separating the scale numbers 60 to 0 ofthe minute drum 4.

In this way the pointer 7 passes from the indication 9 hours 60 minutesto indicate the next hour which is 10 hours 00 minute on drums 4 and 6.

As shownin FIGS. Sand 6, the pointer 7 can be replaced by an indicatorin the form of a movable shutter l8 possessing a window 19 in which onlythe indication of the desired hour appears; the shutter also possesses apointer 20 which moves opposite the minute indicator. An aperture 22 isprovided in a case 21 of the mechanism so that the window remainscompletely visible in its end positions.

In the embodiment represented in FIGS. 1 and 2, the pointer 7 movesconcentrically with the drums, but this requires the use of theintermediate lever 11.

Now according to a simplified further embodiment represented in FIGS. 7and 8, the intermediate lever 11 is dispensed with. In this case themovable shutter 18 is connected by means of arms 24, 24a to a pivotallymovable, eccentrically mounted shaft 23, one of the arms 24 is providedwith a boss 25 which co-operates directly with the cam 15 firmly fixedto the shaft 2.

The operation is identical to that described above, the cam 15co-operating with the boss 25 in the same way as with the boss 14 inorder to shift the movable shutter 18 at substantially the same speed asthe hour drum 6 during each hour.

It will be appreciated that various modifications of the time displaymechanism are possible, for example if the mechanism is to be used toindicate time on a 24 hour basis instead of a 12 hour one as described,the angle a would be 15 instead of 30 as with the illustratedembodiments.

The drums 4 and 6 may be replaced by display rotors in the form of discsor concentrically disposed annular members.

I claim:

1. A time display mechanism for use with a timepiece movement havingseparate hour and minute drive shafts, said mechanism comprising:

a. a first display rotor having indicia thereon representing hours andmeans for mounting said first display rotor on said hour shaft forrotation therewith;

b. a second display rotor having indicia thereon representing to 60minutes with a spacing between a sixty minute mark and a zero minutemark equivalent to the spacing between two successive hour markings onthe first display rotor and means for mounting said second display rotoron said minute shaft for rotation therewith;

an indicator mounted over said first and second display rotors toindicate the time in hours and minutes, said indicator being mounted formovement between first and second positions spaced apart by a distanceequivalent to said spacing between two successive hour markings; and d.indicator moving means for moving said indicator in the same directionas said first display rotor from said first position to said secondposition during each hour and for rapidly shifting said indicator fromsaid second position back to said first position at the end of eachhour, whereby the indicator is moved from said first position to saidsecond position at a speed which is a function of the speed of the firstdisplay rotor to maintain said indicator substantially on the same hourmarking and is rapidly shifted back to its first position at the end ofeach hour in order to indicate the next following hour.

2. A mechanism as claimed in claim 1, wherein the indicator is movablethrough a distance to subtend, about the axis of the minute displayrotor, an angle of 30.-

3. A mechanism as claimed in claim 1, wherein said indicator is freelymovable about said minute shaft and said indicator moving meanscomprises:

a. a support frame;

b. a lever pivotally mounted at one end on said support frame;

0. means for operably coupling the other end of said lever to saidindicator;

d. a cam to be securely fixed to said minute shaft for rotationtherewith; and

e. a cam follower on said lever adapted to engage said cam.

4. A mechanism as claimed in claim 3, wherein said means operablycoupling said lever to said indicator comprises an aperture in saidindicator and a stud on said lever, which stud is engageable in saidaperture.

5. A mechanism as claimed in claim 3, wherein said cam is a disc in theform of a snail cam having a spiral shaped peripheral edge with theminimum and maximum radii points thereof being connected by a radialface and wherein said radial face of said disc is so orientated thatsaid cam follower is at the immediate vicinity of the maximum radiuspoint when said indicator is over the sixtieth minute mark.

6. A mechanism as claimed in claim 3, wherein said lever has an offsetportion intermediate its ends and wherein said cam follower comprises aboss secured to said offset portion of said lever.

7. A mechanism as claimed in claim 1, wherein said indicator comprises apointer.

8. A mechanism as claimed in claim 1, wherein said indicator comprises amovable shutter having a window disposed over said first display rotorand a pointer located opposite said second display rotor.

9. A mechanism as claimed in claim 8, wherein said indicator movingmeans comprises:

a. a cam to be secured to said minute shaft for movement therewith;

b. means mounting said movable shutter for pivotal movement about anaxis offset from that of said first drum, and

c. a cam follower on said last-mentioned means for co-operation withsaid cam.

10. A mechanism as claimed in claim 1, wherein the first and seconddisplay rotors comprise first and second drums, respectively.

1. A time display mechanism for use with a timepiece movement havingseparate hour and minute drive shafts, said mechanism comprising: a. afirst display rotor having indicia thereon representing hours and meansfor mounting said first display rotor on said hour shaft for rotationtherewith; b. a second display rotor having indicia thereon representing0 to 60 minutes with a spacing between a sixty minute mark and a zerominute mark equivalent to the spacing between two successive hourmarkings on the first display rotor and means for mounting said seconddisplay rotor on said minute shaft for rotation therewith; c. anindicator mounted over said first and second display rotors to indicatethe time in hours and minutes, said indicator being mounted for movementbetween first and second positions spaced apart by a distance equivalentto said spacing between two successive hour markings; and d. indicatormoving means for moving said indicator in the same direction as saidfirst display rotor from said first position to said second positionduring each hour and for rapidly shifting said indicator from saidsecond position back to said first position at the end of each hour,whereby the indicator is moved from said first position to said secondposition at a speed which is a function of the speed of the firstdisplay rotor to maintain said indicator substantially on the same hourmarking and is rapidly shifted back to its first position at the end ofeach hour in order to indicate the next following hour.
 2. A mechanismas claimed in claim 1, wherein the indicator is movable through adistance to subtend, about the axis of the minute display rotor, anangle of 30*.
 3. A mechanism as claimed in claim 1, wherein saidindicator is freely movable about said minute shaft and said indicatormoving means comprises: a. a support frame; b. a lever pivotally mountedat one end on said support frame; c. means for operably coupling theother end of said lever to said indicator; d. a cam to be securely fixedto said minute shaft for rotation therewith; and e. a cam follower onsaid lever adapted to engage said cam.
 4. A mechanism as claimed inclaim 3, wherein said means operably coupling said lever to saidindicator comprises an aperture in said indicator and a stud on saidlever, which stud is engageable in said aperture.
 5. A mechanism asclaimed in claim 3, wherein said cam is a disc In the form of a snailcam having a spiral shaped peripheral edge with the minimum and maximumradii points thereof being connected by a radial face and wherein saidradial face of said disc is so orientated that said cam follower is atthe immediate vicinity of the maximum radius point when said indicatoris over the sixtieth minute mark.
 6. A mechanism as claimed in claim 3,wherein said lever has an offset portion intermediate its ends andwherein said cam follower comprises a boss secured to said offsetportion of said lever.
 7. A mechanism as claimed in claim 1, whereinsaid indicator comprises a pointer.
 8. A mechanism as claimed in claim1, wherein said indicator comprises a movable shutter having a windowdisposed over said first display rotor and a pointer located oppositesaid second display rotor.
 9. A mechanism as claimed in claim 8, whereinsaid indicator moving means comprises: a. a cam to be secured to saidminute shaft for movement therewith; b. means mounting said movableshutter for pivotal movement about an axis offset from that of saidfirst drum, and c. a cam follower on said last-mentioned means forco-operation with said cam.
 10. A mechanism as claimed in claim 1,wherein the first and second display rotors comprise first and seconddrums, respectively.